1. Field of the Invention
The present invention relates to apparatus for use in combination with aquariums and more particularly to apparatus for enlarging the volume and viewing area of an existing aquarium tank.
2. Description of the Related Art
Aquariums or fish tanks are commonly available in a range of sizes from 5 gallon tanks to tanks of over 100 gallons. Typically, larger tanks are longer than smaller tanks, while the height of the various size tanks remains generally the same. Thus, as tanks are made larger, the length tends to increase proportionately greater than the height, resulting in a greater horizontal viewing area rather than a greater vertical viewing area.
Inevitably, aquarium hobbyists start with a smaller tank and subsequently find the need or desire to upgrade to a larger tank. Some aquarium enthusiasts may go through several stages of upgrading, each time requiring a breakdown of the existing assembly and setting up of a new, larger aquarium.
While there presently exists no means to "expand" an aquarium tank, there have been various devices and systems developed to enhance the construction of an existing fish tank. One such system of particular interest is disclosed in the patent to Hand, U.S. Pat. No. 5,067,439 directed to a system to facilitate filling and operation of a crossover bridge for attachment to the top of aquarium tanks, wherein a pump is combined with a plurality of end sealing devices on the bridge and a closable aperture in a vacuum portion thereof, to simplify the filling procedure.
Other bridge assemblies are disclosed in the patents to Gibson, Jr., U.S. Pat. No. 3,991,715; Bringman, U.S. Pat. No. 1,943,417; Rice, U.S. Pat. No. 2,512,678; and Polzin, U.S. Pat. No. 1,576,462. While the bridge structures disclosed in these above-referenced patents provide a system for allowing fish to swim upwardly from an aquarium and possibly into an adjacent aquarium tank, they do not effectively enlarge or "expand" the existing tank to yield a larger aquarium. Furthermore, there is no teaching in the related art of a means to maintain a stabilized negative pressure in an upper attached assembly so that the water contained therein will not fall or be released into the lower, preexisting aquarium tank, possibly overflowing therefrom. Due to the fact that most aquariums require an aeration system, to replenish oxygen in the water, it is inevitable that air will rise into a bridge or other vertical highrise structure, eliminating the vacuum that is necessary to hold the water in the structure.